In order to increase the available interior space of a motorized or towable vehicle such as a motor home or trailer, these vehicles have been designed to include slide-out rooms. When the vehicle is in transit, the slide-out room is retracted and stored in the vehicle's interior with the exterior wall of the slide-out room approximately flush with the vehicle's exterior. As a result, there is typically adequate space within the vehicle's interior to accommodate users in transit and remain within the standard width limitations imposed upon a vehicle. When the vehicle is parked and leveled, the slide-out room is then slid outward through an opening formed in a sidewall of the vehicle thereby, increasing the internal accommodations.
Typically, slide-out rooms include a floor section, a roof section, a first sidewall section, a second sidewall section, and a third sidewall section. In the retracted position, the roof section and the first and second sidewall section are concealed from exterior view, and the third sidewall section forms a portion of the vehicle's sidewall. At the same time, the floor section of the slide-out room typically rests above a floor section of a fixed room and may form a portion of the usable interior floor during vehicle transit. Similarly, the roof section of the slide-out room may define the interior ceiling of that part of the vehicle during transit. The proximal ends of the roof section, first sidewall section, and second sidewall section, include stop walls. As used herein, “proximal” refers to the portion towards the vehicle body and “distal” refers to the portion away from the vehicle body. The stop walls form an L-shaped configuration with the respective roof section, first sidewall section and second sidewall section. The stop walls engage the inner surface of a respective sidewall section of the fixed room when the slide-out room is fully extended, and thereby limit the travel of the slide-out room.
Many slide-out room designs include a manual or motorized mechanism for extending or retracting the slide-out room from a vehicle. For example, U.S. Patent Application 20040007890 entitled Room Expansion System, filed Jun. 25, 2003, and U.S. Pat. No. 5,833,296 entitled Motor-operated slide-out drive system with releasable brake, issued Nov. 10, 1998. The contents of each of these applications are hereby incorporated by reference. As seen in these example patents, the slide-out mechanism often includes a gear rack fixed beneath the slide-out room floor with at least one gear mounted to the vehicle and engaged with the gear rack. Thus, the gear rack and slide-out room are moved as the gear rotates either from a manual crank or a connected motor.
A significant benefit to this type of drive gearing is its simplicity. Moreover, heavy-duty gearing used in such a design typically increases the lifespan of the mechanism. Yet, with this type of gearing design most of the motive force is concentrated and exerted at the bottom of the room. This localized load on the bottom surface of the room can often create uneven slide-out conditions between the slide-out room's bottom portion (where the load is concentrated) and the top portion (where there is very little load).
Furthermore, due to the size of some slide-out rooms, the top of the slide-out room may be caused to move relative to bottom if pushed, bumped, or otherwise moved due to the “play” that exists in this type of gearing design. This “play” at the top of the slide-out room can intermittently unseal the slide-out room from the vehicle body when the slide-out room is in the closed position. Thus, dirt, water or other undesirable elements may enter the vehicle body thus making the vehicle interior unsightly or even causing damage.
At times, however, uneven extension or retraction of a slide-out room has been designed into the slide-out mechanism. For example, some prior art flush floor slide-out room designs extend and retract the slide-out room at varying angles to easily and efficiently extend to a flush position with the floor of the main vehicle body. However, it is preferable that the slide-out room retract to a substantially level position. More specifically, for practical reasons, the slide-out mechanism should preferably expand and retract the top and bottom of a slide-out room at different speeds, so as to achieve angled extension and retraction, yet totally retract to a substantially level position.